Airflow control valve structure and intake device

ABSTRACT

An airflow control valve structure includes a metallic pivot shaft- and a valve body. The valve body includes a connection portion connected to the pivot shaft and a resin valve portion. The pivot shaft includes first and second pivot shaft side press-fit portions. The connection portion includes a first valve side press-fit portion formed integrally with the valve portion and a metallic fitting member including a second valve side press-fit portion. The first valve side press-fit portion is fitted to the first pivot shaft side press-fit portion at an angular position at which a phase of the valve portion is matched with a phase of the pivot shaft. The second valve side press-fit portion is fitted to the second pivot shaft side press-fit portion. The first pivot shaft side press-fit portion is longer than the second valve side press-fit portion.

TECHNICAL FIELD

The present invention relates to an airflow control valve structure andan intake device, and particularly to an airflow control valve structureand an intake device including a valve body that controls the flow ofgas supplied to a combustion chamber of an internal combustion engine.

BACKGROUND ART

Patent document 1 describes an example of a conventional airflow controlvalve structure. In the airflow control valve structure, a projectionhaving the form of a triangular post and a connection block having theform of a cylinder formed integrally with a valve body are respectivelyinserted into a recess groove and a through-hole formed in a powertransmission member (crankshaft). Then, the connection block and thethrough-hole are welded through ultrasonic welding to integrally couplethe valve body to the crankshaft.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Chinese Utility Model Publication No. 204492989

SUMMARY OF THE INVENTION Problems that are to be Solved by the Invention

In such an airflow control valve structure, the projection and theconnection block of the valve body are respectively inserted into therecess groove and the through-hole of the power transmission member in astate provided with play. Thus, when the valve body is inserted into thepower transmission member, a phase shift may occur between the valvebody and the power transmission member. Further, even after theinsertion, a similar phase shift may occur during ultrasonic welding.

It is an object of the present invention to provide an airflow controlvalve structure and an intake device that can be integrally coupledwhile reducing a phase shift between a valve body and a powertransmission member.

Means for Solving the Problem

In order to achieve the above object, the airflow control valvestructure according to one embodiment of the disclosure includes ametallic pivot shaft pivoted about a pivot axis and a valve body. Thevalve body includes a connection portion that is connected to the pivotshaft to pivot integrally with the pivot shaft and a resin valve portionthat opens and closes a part of a cross-sectional area of an intakepassage. The pivot shaft includes a first pivot shaft side press-fitportion and a second pivot shaft side press-fit portion that are formedalong the pivot axis. The connection portion includes a first valve sidepress-fit portion formed integrally with the valve portion and ametallic fitting member including a second valve side press-fit portion.The first valve side press-fit portion is fitted to the first pivotshaft side press-fit portion at an angular position at which a phase ofthe valve portion is matched with a phase of the pivot shaft. The secondvalve side press-fit portion is fitted to the second pivot shaft sidepress-fit portion. The first pivot shaft side press-fit portion is setto be longer than the second valve side press-fit portion in dimensionin a pivot axis direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing the structure of anintake device and an airflow control valve structure according to oneembodiment.

FIG. 2 is a cross-sectional view showing the structure of the airflowcontrol valve structure according to the embodiment.

FIG. 3 is a cross-sectional view showing the connection structure of apivot shaft and a connection portion of the airflow control valvestructure according to the embodiment.

FIG. 4A is a front view and FIG. 4B is a side view showing the structureof the pivot shaft of the airflow control valve structure according tothe embodiment.

FIG. 5A is a side view showing the structure of the connection portionof the airflow control valve structure according to the embodiment, FIG.5B is a cross-sectional view taken along line 5B-5B in FIG. 5A, and FIG.5C is a cross-sectional view taken along line 5C-5C in FIG. 5B.

FIG. 6A is a front view showing the structure of a bushing of theairflow control valve structure according to the embodiment, and FIG. 6Bis a cross-sectional view taken along line 6B-6B in FIG. 6A.

FIG. 7A and FIG. 7B are diagrams showing a connection step of the pivotshaft and the connection of the airflow control valve structureaccording to the embodiment.

FIG. 8A is a front view and FIG. 8B is a side view showing the structureof a modified form of the airflow control valve structure.

FIG. 9A is a side view showing the structure of the modified form of theairflow control valve structure, and FIG. 9B is a cross-sectional viewtaken along line 9B-9B in FIG. 9A.

EMBODIMENTS OF THE INVENTION

One embodiment of an airflow control valve structure and an intakedevice will now be described. As shown in FIG. 1, an intake device 1installed in an inline four-cylinder engine for a vehicle draws in air,mixes the air with fuel supplied from an injector, and supplies themixed air (hereafter referred to as “air-fuel mixture”) to a combustionchamber when an intake valve opens in an intake stroke of the engine.The engine compresses and ignites the air-fuel mixture in the combustionchamber to burn the air-fuel mixture. The engine transmits expansionforce resulting from the combustion from a piston to a crankshaft. Thisobtains the driving force of the engine from the crankshaft.

The intake device 1 includes a surge tank 2 and a resin intake manifold3 that forms a plurality of (four) intake passages 31 branching from anoutlet side of the surge tank 2. The direction in which the intakepassages 31 are arranged next to one another is referred to as the Xdirection. One side and the other side (right side and left side inFIG. 1) in the X direction are respectively referred to as the X1 sideand the X2 side.

Outlets of the intake passages 31 are entirely connected to form asubstantially tubular inner wall surface 32 and also form an open end 33that extends around the entire edge of an opening of the inner wallsurface 32. The open end 33 is for connection to a cylinder head (notshown). The open end 33 includes a groove (not shown) into which agasket is fitted.

The intake device 1 also includes an intake control valve 4 serving asan airflow control valve structure in the vicinity of the outlet of theintake manifold 3.

The intake control valve 4 includes a plurality of (four) substantiallytubular holding members 5 fitted into the inner wall surface 32 incorrespondence with the intake passages 31. Each holding member 5includes an opening 5 a having a predetermined opening area(cross-sectional area of flow passage). Two walls 51 of the holdingmember 5 facing each other in the X direction each include asubstantially U-shaped support groove 51 a open toward the intakepassage 31 and communicated in the X direction.

The intake control valve 4 also includes an intake control valve body 6.The intake control valve body 6 includes a plurality of (four) valvebodies 60 arranged next to one another in the X direction.

The valve bodies 60 each include an integrated flat valve portion 62connecting two side walls 61 facing the walls 51 of the holding member 5and distal ends of the two side walls 61 in the X direction. A part ofthe valve portion 62 is cut away to form a control passage portion 62 a.

The side walls 61 of the valve body 60 each include a substantiallyprotruding shaft portion 61 a projecting away from each other in the Xdirection. The shaft portion 61 a is inserted into a substantiallykeyhole-shaped bearing member 52, which opens in the X direction. Thebearing member 52 is fitted into the support groove 51 a of the holdingmember 5 to pivotally support the shaft portion 61 a in cooperation withthe holding member 5. That is, each valve body 60 is pivotal about anaxis extending in the X direction through the holding member 5 and thebearing member 52.

As shown in FIG. 2, the intake control valve body 6 includes a pluralityof (three) connection shafts 63 that connect adjacent valve bodies 60 inthe X direction. That is, the connection shaft 63 is fixed to the shaftportions 61 a of the valve bodies 60 adjacent to the two of theconnection shaft 63. Thus, the valve bodies 60 are all pivotedintegrally about the axis (hereafter referred to as “pivot axis O1”)extending in the X direction.

When the valve portion 62 is in a pivot position in which the valveportion 62 falls along the inner wall surface to open the opening 5 a,the valve body 60 is in an open state that maximizes the open area ofthe opening 5 a. When the valve portion 62 is in a pivot position inwhich the valve portion 62 rises from the inner wall surface to close apart of the opening 5 a, the valve body 60 is in a reduced state thatminimizes the open area of the opening 5 a.

As shown in FIG. 1, a first attachment portion 34 is formed near theoutlet of the intake manifold 3 at the X1 side. An electric actuator 7is attached to the first attachment portion 34.

The electric actuator 7 includes a motor 71, a drive gear 72 serving asa power transmission member, and a metallic pivot shaft 73. The drivegear 72 is driven by and connected to the motor 71 and pivoted about thepivot axis O1. The pivot shaft 73 is substantially cylindrical andincludes a step, concentric with the pivot axis O1, and includes an endat the X1 side connected to the drive gear 72 to be pivoted integrallywith the drive gear 72. An end of the pivot shaft 73 at the X2 side isinserted through the first attachment portion 34 and connected to theadjacent valve body 60, that is, the intake control valve body 6 so asto pivot integrally with the valve body 60. In other words, the pivotshaft 73 and the intake control valve body 6 are integrally pivotingwhen the drive gear 72 pivots about the pivot axis O1.

A mechanical lock unit (not shown) is arranged between the drive gear 72and the intake manifold 3. The mechanical lock unit restricts therotation of the drive gear 72 when the phases of the drive gear 72 andthe intake manifold 3 reach predetermined initial phases (i.e., phasesthat correspond to the open state of the valve body 60). The pivot shaft73 is inserted through an annular sealing member 79 arranged between thepivot shaft 73 and the first attachment portion 34. The sealing member79 prevents the leakage of gas out of the intake passage 31 from betweenthe first attachment portion 34 and the pivot shaft 73.

A second attachment portion 35 is formed near the outlet of the intakemanifold 3 at the X2 side. A sensor unit 8 is attached to the secondattachment portion 35.

The sensor unit 8 includes a metallic pivot shaft 81. The pivot shaft 81is substantially cylindrical and includes a step, concentric with thepivot axis O1, in the same manner as the pivot shaft 73. An end of thepivot shaft 81 at the X1 side is inserted through the second attachmentportion 35 and connected to the adjacent valve body 60, that is, theintake control valve body 6, so as to pivot integrally with the valvebody 60. In other words, the pivot shaft 81 and the intake control valvebody 6 are integrally pivoting when the intake control valve body 6pivots about the pivot axis O1. The sensor unit 8 is configured todetect the pivot position of the pivot shaft 81, that is, opening degreeinformation of the intake control valve body 6. In the same manner asthe pivot shaft 73, the pivot shaft 81 is inserted through an annularsealing member 89 arranged between the pivot shaft 81 and the secondattachment portion 35. Thus, in the intake device 1, the two pivotshafts 73 and 81 and the intake control valve body 6 are pivotedintegrally about the pivot axis O1. The electric actuator 7 isdrive-controlled by an electronic control unit (not shown). Theelectronic control unit drive-controls the electric actuator 7 tocontrol the position of the intake control valve body 6 based oninformation obtained from an operation map in accordance with enginespeed and a load condition. In this case, the electronic control unitperforms feedback control when driving the electric actuator 7 based onthe opening degree information of the intake control valve body 6detected by the sensor unit 8. The connection structure of the pivotshafts 73 and 81 and the adjacent valve body 60 (hereafter also referredto as “valve body 60A”) will now be described. The side walls 61 and thevalve portion 62 of the valve body 60A are formed integrally from aresin material.

As shown in FIG. 3, the shaft portion 61 a of one of the side walls 61(hereafter also referred to as “side wall 61A”) facing the pivot shaft81 of the valve body 60A forms a connection portion 90 connected to thepivot shaft 81. The connection portion 90 includes a resin holdingportion 91 formed integrally with the side wall 61A (and the valveportion 62) and a metallic bushing 92 serving as a fitting memberembedded in the holding portion 91.

The holding portion 91 includes a substantially tubular outer holdingportion 91 a, which is concentric with the pivot axis O1 and projectsfrom the side wall 61A, and a substantially cylindrical inner holdingportion 91 b, which is concentric with the outer holding portion 91 aand projects from the side wall 61A at an inner side of the outerholding portion 91 a. The projecting length of the inner holding portion91 b is set to be smaller than the projecting length of the outerholding portion 91 a. The inner holding portion 91 b includes a firstvalve side press-fit hole 93 serving as a first valve side press-fitportion that is recessed from a distal end surface 91 c toward the sidewall 61A along the pivot axis O1.

As shown in FIGS. 5A to 5C, the first valve side press-fit hole 93 issubstantially oval and defined by two arcuate surfaces 93 a opposingeach other in the radial direction at the opposite sides of the pivotaxis O1 and two flat surfaces 93 b arranged in parallel with the radialdirection and connecting the ends of the arcuate surfaces 93 a.

The bushing 92 is substantially tubular, concentric with the pivot axisO1, and embedded in the holding portion 91 between an inner wall surface91 d of the outer holding portion 91 a and an outer circumferentialsurface 91 e of the inner holding portion 91 b. An outer wall surface 92a of the bushing 92 is in close contact with the inner wall surface 91 dof the outer holding portion 91 a over the entire length of the outerholding portion 91 a. A proximal end portion 92 c of an innercircumferential surface 92 b of the bushing 92 is in close contact withthe outer circumferential surface 91 e of the inner holding portion 91 bover the entire length of the inner holding portion 91 b. The outer wallsurface 92 a and the proximal end portion 92 c form an embedded portion.A distal end portion 92 d of the inner circumferential surface 92 b ofthe bushing 92 projecting from the inner holding portion 91 b forms asubstantially circular second valve side press-fit hole 92 e serving asa second valve side press-fit portion. The open end of the second valveside press-fit hole 92 e is widened by a taper 92 f. The second valveside press-fit hole 92 e is concentric with the pivot axis O1.

As shown in FIGS. 6A and 6B, the central portion of the outer wallsurface 92 a in the direction of the pivot axis O1 includes arecess-projection portion 94 serving as a zigzagged pivoting restrictionportion, which is recessed and projected at equal angular intervals(cyclically) in the radial direction about the pivot axis O1. Therecess-projection portion 94 is shaped to have a substantially uniformcross section along the pivot axis O1. Further, each end of the outerwall surface 92 a in the direction of the pivot axis O1 includes aflange 95 serving as a substantially annular movement restrictionportion that projects outward in the radial direction about the pivotaxis O1. In other words, the recess-projection portion 94 and theflanges 95 of the outer wall surface 92 a mesh with the inner wallsurface 91 d of the outer holding portion 91 a.

As shown in FIGS. 4A and 4B, the pivot shaft 81 includes a substantiallycylindrical pivot shaft body 96 concentric with the pivot axis O1, afirst pivot shaft side press-fit shaft 97 serving as a first pivot shaftside press-fit portion, and a second pivot shaft side press-fit shaft 98serving as a second pivot shaft side press-fit portion.

The second pivot shaft side press-fit shaft 98 is substantiallycylindrical, concentric with the pivot axis O1, and has an outerdiameter set to be the same as the inner diameter of the second valveside press-fit hole 92 e and smaller than the outer diameter of thepivot shaft body 96. The second pivot shaft side press-fit shaft 98 isconcentric with the pivot shaft body 96 and projects from a distal endsurface 96 a, which faces the side wall 61A. The distal end of thesecond pivot shaft side press-fit shaft 98 is reduced in diameter at ataper 98 a.

The first pivot shaft side press-fit shaft 97 is concentric with thesecond pivot shaft side press-fit shaft 98 and projects from a distalend surface 98 b, which faces the side wall 61A. That is, the pivotshaft body 96, the second pivot shaft side press-fit shaft 98, and thefirst pivot shaft side press-fit shaft 97 are arranged in this ordertoward the side wall 61A (valve body 60A).

The first pivot shaft side press-fit shaft 97 is substantially oval anddefined by two arcuate surfaces 97 a, which oppose each other in theradial direction at the opposite sides of the pivot axis O1, and twoflat surfaces (flat portions) 97 b, which are arranged in parallel withthe radial direction and connect the ends of the arcuate surfaces 97 a.The gap between the arcuate surfaces 97 a in the radial direction is setto be smaller than the gap between the arcuate surfaces 93 a of thefirst valve side press-fit hole 93. Further, a chamfered portion 97 c isformed on the entire circumference of the distal end of the first pivotshaft side press-fit shaft 97.

As shown in FIG. 3, the pivot shaft 81 and the connection portion 90(valve body 60A) are connected to be pivoted integrally by press-fittingthe first pivot shaft side press-fit shaft 97 into the first valve sidepress-fit hole 93 and press-fitting the second pivot shaft sidepress-fit shaft 98 into the second valve side press-fit hole 92 e in astate in which the two flat surfaces 97 b are pressed against the twoflat surfaces 93 b. In this case, the arcuate surfaces 97 a are held inabutment with or in the proximity of the arcuate surfaces 93 a. In otherwords, the phases of the pivot shaft 81 and the connection portion 90are restricted when the flat surfaces 97 b are pressed against the flatsurfaces 93 b. Further, the pivot shaft 81 and the connection portion 90(valve body 60A) are more firmly coupled by press-fitting the secondpivot shaft side press-fit shaft 98 into the second valve side press-fithole 92 e of the metallic bushing 92, that is, by press fitting metallicparts.

With respect to the dimensions in the direction of the pivot axis O1,the first pivot shaft side press-fit shaft 97 is set to be longer thanthe second valve side press-fit hole 92 e. That is, as shown in FIGS. 7Aand 7B, in the connection step of the pivot shaft 81 and the connectionportion 90, when moving the pivot shaft 81 toward the connection portion90 along the pivot axis O1, the distal end of the first pivot shaft sidepress-fit shaft 97 passes through the second valve side press-fit hole92 e and abuts on the open end of the first valve side press-fit hole 93thereby starting press-fitting into the first valve side press-fit hole93. In this stage, the distal end of the second pivot shaft sidepress-fit shaft 98 has not reached the open end of the second valve sidepress-fit hole 92 e. Then, the pivot shaft 81 is moved further towardthe connection portion 90 by distance ΔL along the pivot axis O1, andthe distal end of the second pivot shaft side press-fit shaft 98 abutson the open end of the second valve side press-fit hole 92 e, therebystarting press-fitting into the second valve side press-fit hole 92 e.This projection in press fitting of the first pivot shaft side press-fitshaft 97 remains moved ahead of the second pivot shaft side press-fitshaft 98 over distance ΔL until the distal end surface 96 a of the pivotshaft body 96 abuts on the distal end surface of the bushing 92(connection portion 90) and the connection step of the pivot shaft 81and the connection portion 90 ends.

In other words, with respect to the dimensions in the direction of thepivot axis O1, the first pivot shaft side press-fit shaft 97 being setto be longer than the second valve side press-fit hole 92 e indicates asubstantial dimensional difference causing the point in time at whichthe first pivot shaft side press-fit shaft 97 undergoes press-fitting tobe after the point in time at which the second valve side press-fit hole92 e is press-fitted by an amount corresponding to distance ΔL. Thus,this does not indicate a dimensional difference that is non-essential.

The connection structure of the pivot shaft 73 and the valve body 60A isthe same and includes elements denoted with the reference numerals inthe 90 s.

The operation and advantages of the present embodiment will now bedescribed.

(1) In the present embodiment, with respect to the dimensions in thedirection of the pivot axis O1, the first pivot shaft side press-fitshaft 97 is set to be longer than the second valve side press-fit hole92 e. Thus, when connecting the pivot shafts 73 and 81 to the valve body60A, at the connection portions 90 of the valve body 60A, the firstpivot shaft side press-fit shafts 97 of the pivot shafts 73 and 81 arepress-fitted into the first valve side press-fit holes 93 before thesecond pivot shaft side press-fit shafts 98 are press-fitted into thesecond valve side press-fit holes 92 e. In other words, relativepivoting of the pivot shafts 73 and 81 and the valve body 60A isrestricted in a state in which the phases of the pivot shafts 73 and 81and the valve body 60A (and the valve portion 62) are matched inadvance. Then, the second pivot shaft side press-fit shafts 98 of thepivot shafts 73 and 81 are press-fitted into the second valve sidepress-fit holes 92 e of the metallic bushings 92, that is, metallicparts are press-fitted, to further firmly couple the pivot shafts 73 and81 to the valve body 60A. As a result, the electric actuator 7 (and thesensor unit 8) and the valve body 60A (intake control valve body 6) arefurther firmly coupled while reducing phase shifting.

(2) In the present embodiment, the second pivot shaft side press-fitshaft 98 and the first pivot shaft side press-fit shaft 97 are arrangedin this order toward the side wall 61A (valve body 60A). That is, thefirst pivot shaft side press-fit shaft 97 is arranged at the head sidewhen connecting the pivot shafts 73 and 81 and the connection portions90. Thus, the second pivot shaft side press-fit shaft 98 does not affectthe movement (coupling) of the first pivot shaft side press-fit shaft 97regardless of its shape. Accordingly, the surface area of the secondpivot shaft side press-fit shaft 98 per unit length in the direction ofthe pivot axis O1 may be larger than the surface area of the first pivotshaft side press-fit shaft 97 per unit length in the same direction.Further, the contact (press contact) area between the second pivot shaftside press-fit shaft 98 and the second valve side press-fit hole 92 e isincreased. This further firmly couples the pivot shafts 73 and 81 andthe valve body 60A (connection portions 90).

(3) In the present embodiment, the bushing 92 is embedded in the holdingportion 91 such that the bushing 92 is arranged between the inner wallsurface 91 d of the outer holding portion 91 a and the outercircumferential surface 91 e of the inner holding portion 91 b. Thus,the bushing 92 is efficiently arranged without being enlarged in thedirection of the pivot axis O1. Further, the outer wall surface 92 a ofthe bushing 92 is in close contact with the inner wall surface 91 d ofthe outer holding portion 91 a over its entire length, and the proximalend portion 92 c of the inner circumferential surface 92 b of thebushing 92 is in close contact with the outer circumferential surface 91e of the inner holding portion 91 b over its entire length. This furtherfirmly fixes the bushing 92 to the holding portion 91.

(4) In the present embodiment, the second pivot shaft side press-fitshaft 98 and the second valve side press-fit hole 92 e (bushing 92) aresubstantially cylindrical and substantially circular, respectively.Thus, the second pivot shaft side press-fit shafts 98 can bepress-fitted into the second valve side press-fit holes 92 e (bushing92) at any angle. The first pivot shaft side press-fit shafts 97 arepress-fitted into the first valve side press-fit holes 93. Thus, thephases of the pivot shafts 73 and 81 and the valve body 60A that havebeen matched in advance are less likely to be shifted. Further, therecess-projection portion 94 of the bushing 92 restricts pivoting of thebushing 92 relative to the holding portion 91 when the bushing 92closely meshes with the inner wall surface 91 d of the outer holdingportion 91 a (part of holding portion 91).

(5) In the present embodiment, the recess-projection of therecess-projection portion 94 is formed at equal angular intervals aroundthe pivot axis O1. This uniformly disperses twisting force of the pivotshafts 73 and 81 relative to the outer holding portion 91 a (part of theholding portion 91). Further, pivoting of the bushing 92 relative to theholding portion 91 is efficiently restricted with a very simplestructure in which the bushing 92 according to the recess-projection ofthe recess-projection portion 94 meshes with the inner wall surface 91 dof the resin outer holding portion 91 a.

(6) In the present embodiment, the ends of the outer wall surface 92 aof the bushing 92 in the direction of the pivot axis O1 each include thesubstantially annular flange 95 that projects outward in the radialdirection relative to the pivot axis O1. This restricts movement of thebushing 92 in the direction of the pivot axis O1 relative to the outerholding portion 91 a (part of holding portion 91). Thus, displacement ofthe valve body 60A and the pivot shafts 73 and 81 in the direction ofthe pivot axis O1 is reduced in a state in which the pivot shafts 73 and81 and the bushings 92 are press-fitted.

(7) In the present embodiment, displacement of the bushing 92 relativeto the holding portion 91 in the direction of the pivot axis O1 arerestricted with a very simple structure in which the bushing 92including the flange 95 meshes with the inner wall surface 91 d of theresin outer holding portion 91 a (part of the holding portion 91).

(8) In the present embodiment, the first pivot shaft side press-fitshaft 97 and the first valve side press-fit hole 93 respectively includethe flat surface 97 b and the flat surface 93 b, which are very easy tomachine. This matches the phases of the first pivot shaft side press-fitshaft 97 and the first valve side press-fit hole 93 utilizing a verysimple structure.

(9) In the present embodiment, the electric actuator (or the sensor unit8) arranged integrally with the pivot shaft 73 is further firmly coupledto the valve body 60A (intake control valve body 6) while reducing phaseshifting.

(10) In the present embodiment, the outer circumferential surface 91 eof the inner holding portion 91 b is in close contact with the innercircumferential surface 92 b of the bushing 92. This reduces deformationof the inner holding portion 91 b in the radial direction relative tothe pivot axis O1 by the bushing 92 when the metallic first pivot shaftside press-fit shaft 97 is press-fitted into the resin inner holdingportion 91 b (first valve side press-fit hole 93).

The above embodiment may be modified as follows.

The pivot shafts 73 and 81 may be a pivot shaft 181 as shown in FIGS. 8Aand 8B. In other words, the pivot shaft 181 includes a pivot shaft body196 corresponding to the pivot shaft body 96 and a second pivot shaftside press-fit shaft 198 corresponding to the second pivot shaft sidepress-fit shaft 98. A first pivot shaft side press-fit shaft 197 isconcentric with the second pivot shaft side press-fit shaft 198 andprojects from the distal end surface of the second pivot shaft sidepress-fit shaft 198. The first pivot shaft side press-fit shaft 197,which is substantially cylindrical in part, includes a major arc surface197 a that extends about the pivot axis O1 and a flat surface 197 b thatconnects ends of the major arc surface 197 a.

In accordance with this modification, the connection portion 90 may be aconnection portion 190 as shown in FIGS. 9A and 9B. In other words, theconnection portion 190 includes an outer holding portion 191 acorresponding to the outer holding portion 91 a, an inner holdingportion 191 b corresponding to the inner holding portion 91 b, and abushing 192 (second valve side press-fit hole 192 e) corresponding tothe bushing 92. The inner holding portion 191 b includes a first valveside press-fit hole 193 serving as a first valve side press-fit portionrecessed from a distal end surface 191 c along the pivot axis O1. Thefirst valve side press-fit hole 193, which is substantially circular inpart, includes a major arc surface 193 a that extends about the pivotaxis O1 and a flat surface 193 b that connects ends of the major arcsurface 193 a.

In this case, the pivot shaft 181 and the connection portion 190 areconnected to be pivoted integrally when the first pivot shaft sidepress-fit shaft 197 and the second pivot shaft side press-fit shaft 198are respectively press-fitted into the first valve side press-fit hole193 and the second valve side press-fit hole 192 e. This modificationalso has the same advantages as the above embodiment. In addition, thefirst pivot shaft side press-fit shaft 97 includes the two flat surfaces97 b that are required to be shaped by cutting out two surfaces from acylindrical part serving as a material. In contrast, the first pivotshaft side press-fit shaft 197 includes the flat surface 197 b formed bycutting out one surface from a cylindrical material. This reducesmanufacturing steps and costs.

When the pivot shafts 73 and 81 and the connection portion 90 areconnected, two press-contact surfaces at the two flat surfaces 97 b andthe flat surfaces 93 b determine the phase. In contrast, when the pivotshaft 181 and the connection portion 190 are connected, onepress-contact surface at the major arc surface 197 a and the flatsurface 193 b determine the phase. Thus, the capability for reducingphase shifting resulting from the press fitting of the first pivot shaftside press-fit shaft 197 into the first valve side press-fit hole 193 isrelatively inferior to the capability to reduce phase shifts resultingfrom the press fitting of the first pivot shaft side press-fit shaft 97into the first valve side press-fit hole 193.

The phases of the pivot shaft 73 and the connection portion 90 affectthe initial phases of the intake manifold 3 and the drive gear 72 by themechanical lock unit. However, the phases of the pivot shaft 81 and theconnection portion 90 may be adjusted in an electric process wheninitially setting the sensor unit 8. Thus, when replacing one of thepivot shaft 73 and the pivot shaft 81 with the pivot shaft 181, it ispreferred that the pivot shaft 81 be replaced. In this case, the pivotshaft 73 near the electric actuator 7 and the pivot shaft 181 near thesensor unit 8 have different structures. This reduces erroneouscoupling.

In the above embodiment, the recess-projection portion 94 may be formedto be recessed and projected toward the inner holding portion 91 b.

In the above embodiment, the recess-projection portion 94 may berecessed and projected from an end surface of the bushing 92 near theside wall 61A toward the side wall 61A in the direction of the pivotaxis O1.

In the above embodiment, the recess-projection portion 94 may be arecess-projection portion that is recessed and projected in awave-shaped manner, a non-continuous manner, or a non-cyclic manner.Alternatively, the outer wall surface 92 a may have an elliptic shapeinstead of the recess-projection portion 94.

In the embodiment, the recess-projection portion 94 may be omitted.

In the embodiment, the flange 95 of the bushing 92 near the side wall61A may be formed to project toward the inner holding portion 91 b.

In the embodiment, the flange 95 may be formed at any location of thebushing 92 in the direction of the pivot axis O1.

In the embodiment, the flange 95 may be omitted.

In the embodiment, the press-fit structure of the pivot shafts 73 and 81and the valve bodies 60A may be applied to the connection shafts 63 andthe valve bodies 60.

In the embodiment, the first pivot shaft side press-fit shaft 97 and thesecond pivot shaft side press-fit shaft 98 may be arranged in this ordertoward the valve body 60A. The positional relationship between thesecond valve side press-fit hole 92 e and the first valve side press-fithole 93 may be changed accordingly.

In the embodiment, the number of the flat surfaces 93 b, 193 b, 97 b,and 197 b for restricting the phases of the pivot shafts 73, 81, and 181and the connection portions 90 and 190 may be greater than or equal tothree. For example, the first pivot shaft side press-fit shaft 97 and197 may be formed to have the shape of a substantially polygonal columnand the first valve side press-fit holes 93 and 193 may be formedaccordingly to be substantially polygonal.

In the embodiment, the pivot shafts 73, 81, and 181 include the firstpivot shaft side press-fit portion and the second pivot shaft sidepress-fit portion that are formed to be cylindrical (first pivot shaftside press-fit shaft 97 and 197 and the second pivot shaft sidepress-fit shaft 98 and 198). The connection portions 90 and 190 includethe first valve side press-fit portion and the second valve sidepress-fit portion that are formed to be hole-shaped (first valve sidepress-fit hole 93 and 193 and second valve side press-fit hole 92 e and192 e). However, the pivot shafts 73, 81, and 181 may include the firstpivot shaft side press-fit portion and the second pivot shaft sidepress-fit portion that are formed to be hole-shaped, and the connectionportions 90 and 190 may include the first valve side press-fit portionand the second valve side press-fit portion that are formed to becylindrical.

1. An airflow control valve structure, comprising: a metallic pivotshaft pivoted about a pivot axis; and a valve body including aconnection portion that is connected to the pivot shaft to pivotintegrally with the pivot shaft and a resin valve portion that opens andcloses a part of a cross-sectional area of an intake passage, whereinthe pivot shaft includes a first pivot shaft side press-fit portion anda second pivot shaft side press-fit portion that are formed along thepivot axis, and the connection portion includes a first valve sidepress-fit portion formed integrally with the valve portion, wherein thefirst valve side press-fit portion is fitted to the first pivot shaftside press-fit portion at an angular position at which a phase of thevalve portion is matched with a phase of the pivot shaft, and a metallicfitting member including a second valve side press-fit portion fitted tothe second pivot shaft side press-fit portion, wherein the first pivotshaft side press-fit portion is set to be longer than the second valveside press-fit portion in dimension in a pivot axis direction.
 2. Theairflow control valve structure according to claim 1, wherein the pivotshaft extends along the pivot axis such that the second pivot shaft sidepress-fit portion and the first pivot shaft side press-fit portion arearranged in order toward the valve body.
 3. The airflow control valvestructure according to claim 1, wherein the connection portion includesa holding portion formed integrally with the valve portion, and thefitting member includes an embedded portion embedded in the holdingportion.
 4. The airflow control valve structure according to claim 3,wherein the second pivot shaft side press-fit portion is cylindricalcolumnar and the second valve side press-fit portion is tubular,respectively, and the embedded portion includes a pivoting restrictionportion that restricts pivoting relative to the holding portion.
 5. Theairflow control valve structure according to claim 4, wherein thepivoting restriction portion includes a recess-projection portion thatis recessed and projected at equal angular intervals in a radialdirection about the pivot axis.
 6. The airflow control valve structureaccording to claim 3, wherein the embedded portion includes a movementrestriction portion that restricts movement of the embedded portion inthe pivot axis direction relative to the holding portion.
 7. The airflowcontrol valve structure according to claim 6, wherein the movementrestriction portion includes a flange at a predetermined location in thepivot axis direction, and the flange projects in a radial directionabout the pivot axis.
 8. The airflow control valve structure accordingto claim 1, wherein the first pivot shaft side press-fit portion and thefirst valve side press-fit portion include flat portions formed alongthe pivot axis and abut against each other.
 9. An intake devicecomprising: the airflow control valve structure according to claim 1;and a power transmission member rotated integrally with the pivot shaft.